diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index 66c2056..eac6e6f 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -72,7 +72,7 @@ function! ale#completion#OmniFunc(findstart, base) abort
         let l:line = b:ale_completion_info.line
         let l:column = b:ale_completion_info.column
         let l:regex = s:GetRegex(s:omni_start_map, &filetype)
-        let l:up_to_column = getline(l:line)[: l:column - 1]
+        let l:up_to_column = getline(l:line)[: l:column - 2]
         let l:match = matchstr(l:up_to_column, l:regex)
 
         return l:column - len(l:match) - 1